Cenozoic distributed rotational deformation, South Island, New Zealand
Cenozoic distributed rotational deformation, South Island, New Zealand
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新生代分布旋转变形，新西兰南岛
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
C. Mac Niocaill
中科院分区：
文献类型：
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作者：
L. Hall;S. Lamb;C. Mac Niocaill
来自新西兰马尔伯勒地区的新的构造和古地磁数据为南岛造山斜的形成时间提供了更好的约束。这些数据表明，在新近纪期间，地壳在板块边界带的这一部分发生了约100°的顺时针弯曲，其中大部分发生在早中新世至晚中新世(约25-8 Ma)之间，这意味着分布剪切是新近纪有限应变调节的重要机制。一个简单的运动学模型表明，这种分布的变形是通过平行于主组构的细长块体的旋转来适应的，以响应下面岩石圈地幔中的连续变形。在晚中新世板块运动引入显著的会聚分量后，分布变形在马尔伯勒断裂带中央可能不再起到如此重要的作用，运动变得集中在马尔伯勒断层本身。然而，在马尔伯勒东北部，自那时以来，∼发生了额外的顺时针旋转35°，这可能是由于地壳重组为更等维的块体，在那里它们终止于希库兰吉边缘。
New structural and paleomagnetic data from the Marlborough region, New Zealand, provide better constraints on the timing of the formation of the South Island orocline. These data indicate that approximately 100° of clockwise bending of the crust has occurred across this part of the plate boundary zone during the Neogene, most of which took place between the early and late Miocene (circa 25–8 Ma), implying that distributed shear has been an important mechanism in the accommodation of Neogene finite strain. A simple kinematic model suggests that this distributed deformation has been accommodated by the rotation of elongate blocks parallel to the main fabric, in response to continuous deformation in the underlying lithospheric mantle beneath. After the introduction of a significant convergent component to the plate motion in the late Miocene, distributed deformation may have ceased to play such a significant role in the central Marlborough fault zone, with motion becoming concentrated on the Marlborough faults themselves. In the northeastern part of Marlborough, however, an extra clockwise rotation of ∼35° has occurred since this time, which might be explained by the reorganization of the crust into more equidimensional blocks where they terminate against the Hikurangi margin.